Mirror



May 13 19221.

M. J. RITTERRATH MIRROR Original. Filed July 5. 192) INVENTOR. Zo/X/ J Y/f/` i ATT'oR EY lPatented May 1.3, 1924.

.MAX J. RITTERRATH, HOLLYWOOD, CALIFORNIA.

MIRROR.

Application led July 3, 1920, Serial No. 393,842. Renewed October 11,1923.

To all whom it 411,04/ concern:

Be 1t known that I, MAX J. RITTERRATH, a

l citizen of the United States, residing at Hollywood, Los Angeles, in the county of Los Angeles and State of California, haveI invented a new and useful Mirror, of which the following is a specification.

This invention relates to mirrors of the type capable of being used in connection w1th relatively intense sources .of light, for .example the arc light, and an object of the invention is to effect cooling of the mirror.

Another object 1s to make provision for circulatlng the cooling medlum of the m11'- ror.

in one form of the invention so that the lcooling medium will also function asa -refiecting medium to reflect the light rays.

In moving picture projectors, because of .v the intense heat of the arc, it is customary to employ the arc without a mirror and thus much of the light furnished by the arc is dissipated and lost. Besides this, the usual construction of motion picture projectors is l such that the light rays are highly concentrated in the plane occupied by the film, and to still further concentrate them would make more liable burning up of the film if it should be stopped for a slightly longer interval of time than is usually required in the projection thereof. Thus with the ordinary arrangement of lenses in the projectors it is not desirable to employ a reiiector. This mirror is especially useful as an ele- .ment of the apparatus for projecting the images on motion picture lms disclosed in my copending application, Serial No.

387,557, filed June 9, 1920,'since in said application the combination ofrlenses and the method of cooling or interrupting the radiant heat produced by the light source permits of the use of a mirror. In fact,in the apparatus which is the subject of said copending application, it is highly desirable'- to emp y a mirror, but the ordinary mirror could not be used because of distortionthereof which the intense heat would cause.'

This mirror may be used wherever the source of light is of-such great intensity as Wouldcause relatively great expansion of the mirror or, as often happens, breakage thereof if the mirror were of the ordinary character. Even thou h the mirror is not broken by the intense eat, it is clear that in projection work, where it is so important y j 23, 24 bottom 4, top 5, rear wall 6, and front Another object is to construct the mirrort; wall. In the drawings the greater portion of the wall 8 is of parabolic conformation,

tof :thy other suitable externally concave shape.

In the form of the invention shown in Figs. 1 to 3, the frontv wall 8-is formed of a lighttraiismitting substance such as glass so that flight rays can be transmitted thereby to the rear surface of said front wall.

The chamber 1 is vsupplied with a cooling medium indicated as a liquid 10 which, in this instance, is a. refiector of light ras. The cooling medium in Fig. 5 may be, or example, mercury. The surface of the mercury adjacent the light transmitting wall 8 forms a reflector or mirror surface adapted to reflect light rays transmitted through the wall 8.

Electrodes are indicated in dotted lines at 11, 12 as indicating a source oflight, but they are not a part of the invention.

Not only is circulation of the cooling medium provided for, but expansion thereof is also provided for and the construction for permitting this is as follows: Passing but is understood that it may be made l through the rear Wall 6 and communicating 1with the lower portion of the chamber 1 is a tube 17, and the upper end of said tube passes through the to 18 of an ex- 4painsion chamber or reservoir 19. The botits lower', end with the top 5 `of the chamber 1, thus aiording communication between the chambers 1, 19. Y

In Fig. 1 as the cooling medium becomes heated from the heat produced by the light source, it expands, and the chamber 19, not being ull when the mirror is cool, permits the mercury to expand into said chamber. It may be that the .heat will even be sufficient to` vaporize the mercury and, in that event, the mercury will expand and flow through the tube 26 into the chamber 19 where 1t Will vaporize and then cool and condense. -From the chamber 19 the liquid mercury will pass" downwardly through the tube 17 to the lower portion of the chamber 1.

The front wall 8 is provided with a rearwardly projecting stud 27 engaging a recess 28 formed in the rear wall 6.

The tube 17 is partially accommodated in a chamber 29 formed rearwardly of the chamber 1, the front wall of the chamber 29 being the wall 6, the rear wall being indicated at 30, the side walls atV 31, 32,

the top at 33 and the bottom at 34. The

walls 23, 24 extend upwardly at the sidc' of the chamber 19 from the bottom al d are spaced from the side walls 31,1132 of vsaid chamber and the upper portionfo the tube 17 passes through the -s ace betwec.; the wall 31 and wall 23 as c early shown in Fi 2.

I c aim:

1. A mirror comprisin means forming a chamber, the front wa of the chamber bein of light-transmitting material, a liquid ight-reecting medium in the chamber in contact with the light-transmittin wall and forming the reiecting surface o the mirror, and means to circulate and cool the li ht-refiecting medium.

2. mirror comprising means formn a chamber, the front wall of the chamber ieing of light-transmittin material, a body of mercury in the cham er in contact with the light-transmitting wall and forming the reflecting surface of the mirror, and means to circulate and cool the mercury.

3. A mirror comprising means forming a chamber, the front wall of the chamber bein of light-transmitting material, a. liquid ight-reflecting medium in the chamber in contact with the light-transmitting wall and forming the reflecting surface of the mirror, and means forming a cooling chamber connected with the up er and lower portions of the first-named c amber.

4. A mirror comprisin means forming a chamber, the front wal of the chamber bein of light-transmitting material, a liquid ight-reflecting medium in the chamber in contact with the lightftransmitting wall and forming the reiiecting surface of the mirror, and means forming a vapor connsing chamber connected with the upper .d lower portions of the first named chaml e. and rovided with heat-radiating tins.

*..Signe at Los Angeles, California, this 29th day of June 1920.

MAX J. RITTERRATH.

Witnesses:

GEORGE H. Hume, L. Bumm Wmvnn. 

